Project Abstract/Summary This R35 MIRA grant application is designed to investigate mechanisms responsible for the exaggerated effects of alcohol intoxication on multi-organ system responses after burn injury. Of the million people per year who suffer burn injuries in the U.S., nearly half of the adult patients are intoxicated at the time of injury. Intoxicated burn patients have increased morbidity and mortality compared to those who had not been drinking. The lung is the most frequent organ to fail after a remote injury such as cutaneous burn, with 45% of burn patients showing some form of lung damage even in the absence of inhalation injury. Pneumonia and acute respiratory distress syndrome (ARDS) are among the major complications seen in intoxicated burn patients. Little is known about the mechanism by which alcohol intoxication upregulates the post-burn systemic inflammatory responses that lead to excessive pulmonary inflammation and increased susceptibility to lung infection. Recently, we reported that the post-burn pulmonary inflammatory response is exacerbated in intoxicated subjects because of a breach in the integrity of the intestinal epithelial barrier secondary to burn. This, along with dysbiosis of the fecal microbiome, could be critically involved in the systemic inflammation seen after burn injury. We and others have shown that burn trauma and alcohol intoxication independently cause these intestinal changes and that, after the ?two hit? insult of alcohol and burn injury, these responses are amplified, which could result in a more dramatic shift in the microbiome and a greater release of bacterial products and endotoxins into the circulation, triggering systemic inflammation and damage to distant organs like the lung. To date, we know very little about how and when the intestine recovers from remote injury, such as a cutaneous scald burn, and even less about how factors including alcohol intoxication prior to injury alter that process. In this research program, we will use our clinically-relevant murine model of alcohol intoxication and burn injury along with burn patients, some of whom will have consumed alcohol prior to sustaining their injuries, to address the following questions: 1) What are the effects of alcohol intoxication and burn injury on the gut, specifically, the integrity of the intestinal epithelial barrier and the fecal microbiome, and how long do they last? 2) Can intestinal epithelial cell barrier dysfunction be accurately monitored by measuring plasma biomarkers of intestinal epithelial cell damage, microbial translocation and inflammation, rather than by more invasive tests? 3) Are there gut-directed therapies that can restore the intestinal barrier and microbial homeostasis, which, by virtue of reducing systemic inflammation, will improve the function of distal organs, such as the lung? Taken together, these studies will expand the knowledge of how alcohol exposure alters the gut in the context of remote injury such as burns and may lead to the development of novel therapies for the treatment of patients with burns and other forms of trauma.